1. Field of the Invention
The present invention relates to a method for producing dried microbial cells by subjecting a variety of fermentation microbial cells and microbial cells in activated sludge or the like to a heat treatment without lowering the quality thereof.
2. Brief Description of the Related Art
A method in which microbial cells in a fermentation broth are concentrated by membrane filtration or using a centrifuge or the like, and the resulting dense microbial cell suspension was dried by spraying in a fluidized dryer is generally used.
For example, in Patent document 1 (JP-A-5-123165), a method in which a suspension of an amino acid fermentation microorganism is dried using a rotary disc evaporator, followed by further drying using a closed dryer has been disclosed. In this method, dried microbial cells are prepared in a flake form for the purpose of improving the handling of the dried microbial cells which are conventionally in a fine powder form, and heating is performed at a high temperature for 1 hour or more using steam in both two drying steps.